The invention provides a preparation method of an anti-PID (potential induced degradation) type solar cell encapsulation EVA (ethylene-vinyl acetate copolymer) film, and the preparation method is as follows: raw materials are mixed evenly, and then put into a double screw extruder for blending; the extrudate forms a film by curtain coating and extruding, and the film is coated with a coupling agent in a spray zone, then is dried and rolled for preparation of the anti-PID type solar cell encapsulation EVA film product. Through control of the double screw rod extruder operating temperature, extrusion speed and coupling agent solution spray volume, the anti-PID type solar cell encapsulation EVA film with high volume resistivity, excellent water resistance and good adhesion can be obtained.