I tried to use the raw data only with annotations of muscle artifacts, not using notch filtering, the ecg component couldn’t be found again.
I’m considering that whether it’s the problem of the original heartbeats 
because when I draw the heartbeats evoked plots, it really seems not like heartbeat waves as shown in the tutorial:
Here is the drawing code:
ecg_evoked = create_ecg_epochs(raw_perception, reject_by_annotation=True).average()
ecg_evoked.apply_baseline(baseline=(None, -0.2))
fig_raw_evoked_ecg = ecg_evoked.plot_joint()