Thanks for the advice.
I reduce the max pwm to 80,run M303 and the autotune finished
.
00:35:32.802 : Info:PID Autotune start
00:37:29.424 : bias: 73 d: 73 min: 147.37 max: 157.95
00:37:59.859 : bias: 68 d: 68 min: 146.98 max: 153.69
00:38:29.851 : bias: 67 d: 67 min: 147.17 max: 153.24
00:38:29.851 : Ku: 14.06 Tu: 29.98
00:38:29.851 : Classic PID
00:38:29.851 : Kp: 8.44
00:38:29.851 : Ki: 0.56
00:38:29.851 : Kd: 31.61
00:38:59.622 : bias: 66 d: 66 min: 147.27 max: 153.18
00:38:59.622 : Ku: 14.21 Tu: 29.77
00:38:59.622 : Classic PID
00:38:59.622 : Kp: 8.53
00:38:59.622 : Ki: 0.57
00:38:59.622 : Kd: 31.73
00:39:29.460 : bias: 66 d: 66 min: 147.27 max: 153.01
00:39:29.460 : Ku: 14.63 Tu: 29.77
00:39:29.460 : Classic PID
00:39:29.460 : Kp: 8.78
00:39:29.460 : Ki: 0.59
00:39:29.460 : Kd: 32.67
00:39:29.460 : Info:PID Autotune finished ! Place the Kp, Ki and Kd constants in the Configuration.h or EEPROM
Then I restarted the printer,set the target temperature to 180 °C,but it still swings from 177°C to 186 °C