diff --git a/GA/selection b/GA/selection
new file mode 100644
index 0000000..25702f6
--- /dev/null
+++ b/GA/selection
@@ -0,0 +1,25 @@
+function [idx1,idx2] = selection(PopulationSize,FitnessSum,PopulationFitness,Index)
+%轮盘赌法，确定要交叉的父母编号
+        %确定要交叉的父亲序号
+        m1=0;
+        r1=rand*FitnessSum;
+        for k=1:PopulationSize
+            m1=m1+PopulationFitness(k);
+            if r1<=m1
+                idx1=Index(k);
+                break;
+            end
+        end
+         %确定要交叉的母亲序号
+        m2=0;
+        r2=rand*FitnessSum;
+        for k=1:PopulationSize
+            m2=m2+PopulationFitness(k);
+            if r2<=m2
+                idx2=Index(k);
+                break;
+            end
+        end
+    
+end
+