The invention discloses a copper and silicon catalyst for preparing ethanediol by hydrogenating dimethyl oxalate and a preparation method thereof. The copper and silicon catalyst is prepared by a one-pot method under conditions of taking ester orthosilicate as a silicon source and taking alcohol as a cosolvent and is concretely prepared in such a way that the ester orthosilicate is hydrolyzed andaged in a water-alcohol mixing solution of a copper ammonia complex, and then moisture, alcohol and ammonia are evaporated to enable copper components inside a copper ammonia solution to be uniformlysubsided, and finally washing, drying, roasting and reducing are carried out. The copper and silicon catalyst comprises copper and silicon dioxide, wherein the mol ratio of the copper to the silicon dioxide is 0.05-0.4 to 1. The copper and silicon catalyst shows very high reaction activity and selectivity in the reaction for preparing the ethanediol by hydrogenating the dimethyl oxalate and within a wider temperature range, is easy to operate and beneficial to industrial application.