The invention discloses an epoxy universal primer for ships and a preparation method thereof. The epoxy universal primer for the ships comprises components A and components B, wherein the components A comprise the following components in percentage by weight: high molecular weight epoxy resin, low molecular weight liquid bisphenol A epoxy resin, thixotropic agent, dimethylbenzene, organic soil, wetting dispersant, titanium dioxide, carbon black, iron oxide yellow, talcum powder, feldspar powder, C9 resin, isobutyl alcohol and silane auxiliaries; the components B comprise the following components in percentage by weight: polyamide curing agent and epoxy curing accelerator; in a using process, the mixing mass ratio of the components A to the components B is (6-7) to 1. The epoxy universal primer for the ships provided by the invention can be coated to 400 microns by one step without sagging, saves coating time, can be directly matched with the original coating without a transitional layer, is simple to construct, easy to grasp, and time-saving and labour-saving.