diff --git a/src/GraphStructure.ts b/src/GraphStructure.ts
index 131c6a2..8e55e4f 100644
--- a/src/GraphStructure.ts
+++ b/src/GraphStructure.ts
@@ -26,6 +26,18 @@ export function hasMultipleEdges(g: Graph) {
   return g.edges().some(({ source: s, target: t }) => edgeSet[s].size === edgeSet[s].add(t).size);
 }
 
+export function isSimple(g: Graph, directed: boolean = false): boolean {
+  let edgeSet = Array.from({ length: g.nodes().length }, () => new Set<number>());
+  return g
+    .edges()
+    .some(
+      e =>
+        e.source === e.target ||
+        edgeSet[e.source].size === edgeSet[e.source].add(e.target).size ||
+        (!directed && edgeSet[e.target].size === edgeSet[e.target].add(e.source).size)
+    );
+}
+
 const emptyObject = () => ({});
 
 /**
@@ -68,8 +80,7 @@ export function fromRandom(
 }
 
 export class NodeEdgeList implements Graph {
-  constructor(protected _nodes: Node[], protected _edges: Edge[]) {
-  }
+  constructor(protected _nodes: Node[], protected _edges: Edge[]) {}
 
   static from(g: Graph) {
     return new NodeEdgeList(g.nodes(), g.edges());
@@ -351,4 +362,4 @@ export class GridGraph implements Graph {
   nodes(): Node[] {
     throw new Error(".graph.grid.unsupported");
   }
-}
\ No newline at end of file
+}
diff --git a/src/algorithms/matching/Matching.tsx b/src/algorithms/matching/Matching.tsx
index 81f735c..dcf2b49 100644
--- a/src/algorithms/matching/Matching.tsx
+++ b/src/algorithms/matching/Matching.tsx
@@ -1,5 +1,5 @@
 import { NewGraphAlgorithm, ParameterDescriptor, Step } from "@/GraphAlgorithm";
-import { AdjacencyList, hasMultipleEdges, hasSelfLoop, Edge, Graph, Node, NodeEdgeList } from "@/GraphStructure";
+import { AdjacencyList, hasSelfLoop, Edge, Graph, Node, NodeEdgeList, isSimple } from "@/GraphStructure";
 import { Queue } from "@/utils/DataStructure";
 import NetworkGraphRenderer from "@/ui/render/NetworkGraphRenderer";
 import GraphMatrixInput from "@/ui/input/GraphMatrixInput";
@@ -15,7 +15,11 @@ export class EdmondsGabow_alpha implements NewGraphAlgorithm {
   // TODO: no self loop, no multiple edges
   graphInputComponent = (
     <GraphMatrixInput
-      checker={g => g}
+      checker={g => {
+        if (hasSelfLoop(g)) throw new Error(".input.error.self_loop");
+        if (!isSimple(g)) throw new Error(".input.error.multiple_edges");
+        return g;
+      }}
       formatters={[new EdgeListFormatter(false, false)]}
       description={"Please input a graph without self loop and multiple edges"}
     />
@@ -211,9 +215,7 @@ export class EdmondsGabow_alpha implements NewGraphAlgorithm {
   }
 
   *run(graph: Graph): Generator<Step> {
-    if (hasSelfLoop(graph)) throw new Error("algo Gabow : self loop");
     this.adjlist = AdjacencyList.from(graph, false);
-    if (hasMultipleEdges(this.adjlist)) throw new Error("algo Gabow : mutiple edges");
     this.edges = graph.edges();
     this.nodes = graph.nodes();
     this.n = this.nodes.length;
diff --git a/src/locales/en-US.js b/src/locales/en-US.js
index 8fb16d4..99fc45e 100644
--- a/src/locales/en-US.js
+++ b/src/locales/en-US.js
@@ -83,11 +83,13 @@ module.exports = {
       not_square: "Not a matrix",
       not_matrix: "Not a square matrix",
       asymmetric: "Not a symmetric matrix",
-      edge_count_incorrect: "incorrect edge count",
-      edge_format_incorrect: "incorrect edge format",
+      edge_count_incorrect: "Incorrect edge count",
+      edge_format_incorrect: "Incorrect edge format",
       no_weight: "No weight",
       non_increment: "Non increment",
       invalid_format: "Invalid format",
+      self_loop: "Self-loop found",
+      multiple_edges: "Multiple-edges found",
       network: {
         no_flow: "No flow",
         no_cost: "No cost"
diff --git a/src/locales/zh-CN.js b/src/locales/zh-CN.js
index b44a099..1cf9294 100644
--- a/src/locales/zh-CN.js
+++ b/src/locales/zh-CN.js
@@ -88,6 +88,8 @@ module.exports = {
       no_weight: "输入没有权值",
       non_increment: "输入不递增",
       invalid_format: "输入格式非法",
+      self_loop: "输入存在自环",
+      multiple_edges: "输入存在重边",
       network: {
         no_flow: "输入没有流量",
         no_cost: "输入没有权值"