An electrical connector assembly method, including the steps of: step 1: providing a terminal having a soldering portion; step 2: heating the soldering portion to a melting temperature of a solder; step 3: providing the solder, and press-fitting the solder to the soldering portion by a jig, so that the solder is fused and fixed to the soldering portion; and step 4: inserting the terminal fixed with the solder into an insulating body. Because only the soldering portion of the terminal is heated, less thermal energy is needed, thereby saving energy and reducing the production cost of the electrical connector. Moreover, the insulating body does not need to be heated, thus preventing the insulating body from being warped and deformed due to heat.