The invention provides a manufacture method of a top electrode of a phase transition random memory. The method comprises the following steps: providing a semiconductor substrate, and forming a second insulating layer on the semiconductor substrate, wherein, the second insulating layer is filled with GST phase transition material; depositing a low temperature oxide layer, a silicon nitride layer and a third insulating layer on the second insulating layer and the GST phase transition material in order; etching the third insulating layer and the silicon nitride layer to expose the low temperature oxide layer at a bottom and form an etching hole; carrying out ion implantation processing or plasma processing on the low temperature oxide layer in a bottom of the etching hole; removing the low temperature oxide layer in the bottom of the etching hole; forming the top electrode in the etching hole. According to the invention, the low temperature oxide layer and the silicon nitride layer which are deposited in order are taken as a barrier layer of top electrode etching, when etching the low temperature oxide with a wet method, an etching selectivity ratio larger than 15 is provided between the low temperature oxide layer and the GST phase transition material, thus loss of the GST phase transition material in etching is avoided.