The invention relates to a catalyst for oxalate synthesis by gaseous CO coupling, and mainly overcomes problems in the prior art, namely low catalyst activity, and a low nitrite conversion rate and a low space-time yield of oxalate in processes of synthesizing oxalate from gaseous phase carbon monoxide. According to a technical scheme adopted by the catalyst, the catalyst comprises 1) 0.03-3 wt% of palladium, 2) 0.05-4 wt% of a lanthanide series metal or an oxide thereof, 3) 0-3 wt% of at least one group VIII metal or an oxide thereof, and 4) 90-99.8 wt% of at least one carrier selected from aluminium oxide, silicon dioxide or a molecular sieve. The problems are overcome by adoption of the technical scheme. The catalyst can be used for industrial production of oxalate synthesized by gaseous CO coupling.