A　new　simple　approach　basing　on　the　histogram　and　genetic　algorithm(GA)　to　efficiently　detect　QRS-T　complexes　of　the　ECG　curve　is　described,　so　as　to　easily　get　the　P-wave　(when　AF　does　not　happen)　or　the　f-wave　(when　AF　happens).　By　means　of　signal　processing　techniques　such　as　the　power　spectrum　function,　the　auto-correlation　function　and　cross-correlation　function,　two　kinds　of　ECG　signal　when　AF　does　or　does　not　happen　were　successively　analyzed,　showing　the　evident　differences　between　them.