An insulation monitoring method for a traction battery, wherein the method comprises: obtaining, by taking a current moment as a starting time, each insulation resistance value of the traction battery that is received within a first preset time period before the current moment; collecting data statistics on the obtained insulation resistance values, and analyzing, based on a data statistical result, whether the traction battery has a risk of insulation deterioration; and if the traction battery has the risk of insulation deterioration, outputting first alarm information; characterized in that the step of "collecting data statistics on the obtained insulation resistance values, and analyzing, based on a data statistical result, whether the traction battery has a risk of insulation deterioration" specifically comprises: separately performing mean and variance calculations on the insulation resistance values received within the first preset time period, to obtain a mean insulation resistance value res_avg and an insulation resistance value variance res_std; arranging, in ascending order, the insulation resistance values received within the first preset time period, and calculating a cumulative percentage corresponding to each arranged insulation resistance value; obtaining an insulation resistance value res_Npct corresponding to a cumulative percentage whose percentage value is a preset value N; and analyzing, based on res_avg, res_std, and res_Npct, whether the traction battery has the risk of insulation deterioration, specifically comprising the following case: if { res _ avg < res _ avg _ set res _ Npct < res _ avg _ set res _ std < res _ std _ set, the traction battery has the risk of insulation deterioration, wherein res_avg_set is a preset value for the mean insulation resistance value, and res_std_set is a preset value for the insulation resistance value variance. obtaining, by taking a current moment as a starting time, each insulation resistance value of the traction battery that is received within a first preset time period before the current moment; collecting data statistics on the obtained insulation resistance values, and analyzing, based on a data statistical result, whether the traction battery has a risk of insulation deterioration; and if the traction battery has the risk of insulation deterioration, outputting first alarm information; characterized in that the step of "collecting data statistics on the obtained insulation resistance values, and analyzing, based on a data statistical result, whether the traction battery has a risk of insulation deterioration" specifically comprises: separately performing mean and variance calculations on the insulation resistance values received within the first preset time period, to obtain a mean insulation resistance value res_avg and an insulation resistance value variance res_std; arranging, in ascending order, the insulation resistance values received within the first preset time period, and calculating a cumulative percentage corresponding to each arranged insulation resistance value; obtaining an insulation resistance value res_Npct corresponding to a cumulative percentage whose percentage value is a preset value N; and analyzing, based on res_avg, res_std, and res_Npct, whether the traction battery has the risk of insulation deterioration, specifically comprising the following case: if { res _ avg < res _ avg _ set res _ Npct < res _ avg _ set res _ std < res _ std _ set, the traction battery has the risk of insulation deterioration, wherein res_avg_set is a preset value for the mean insulation resistance value, and res_std_set is a preset value for the insulation resistance value variance. separately performing mean and variance calculations on the insulation resistance values received within the first preset time period, to obtain a mean insulation resistance value res_avg and an insulation resistance value variance res_std; arranging, in ascending order, the insulation resistance values received within the first preset time period, and calculating a cumulative percentage corresponding to each arranged insulation resistance value; obtaining an insulation resistance value res_Npct corresponding to a cumulative percentage whose percentage value is a preset value N; and analyzing, based on res_avg, res_std, and res_Npct, whether the traction battery has the risk of insulation deterioration, specifically comprising the following case: if { res _ avg < res _ avg _ set res _ Npct < res _ avg _ set res _ std < res _ std _ set, the traction battery has the risk of insulation deterioration, wherein res_avg_set is a preset value for the mean insulation resistance value, and res_std_set is a preset value for the insulation resistance value variance. if { res _ avg < res _ avg _ set res _ Npct < res _ avg _ set res _ std < res _ std _ set, the traction battery has the risk of insulation deterioration, wherein res_avg_set is a preset value for the mean insulation resistance value, and res_std_set is a preset value for the insulation resistance value variance.