The invention discloses a control method for defrosting of an air energy heat pump judging a dewpoint. The control method includes the following steps that firstly, a defrosting judging period Dt is preset; secondly, a real-time dewpoint temperature T1 of the outside environment is judged, and temperature T2 of an evaporator coil pipe is detected; thirdly, if T2 is larger than 0 DEG C, a defrosting program of a set is not started; and if T2 is smaller than or equal to 0 DEG C, and delta t1 is delayed to start the defrosting program, wherein delta t1=k1/(T1-T2); fourthly, when the temperature of the evaporator coil pipe reaches a set temperature T, defrosting of the set stops, wherein T is larger than 0 DEG C; fifthly, when the defrosting interval meets Dt, a real-time dewpoint temperatureT3 of the outside environment at the moment is judged again, temperature T4 of the evaporator coil pipe is acquired, and delayed correction time delta t2 is calculated, wherein delta t2=k2/(T3-T4); and sixthly, after the defrosting interval is delayed by the set by delta t2, the steps from the first step to the fifth step are repeated, repeating is performed in this way, and defrosting control ismade to achieve an optimal effect.