Polyoxymethylene dimethyl ethers (PODEn) were synthesized via the reaction between dimethoxymethane (DMM) and trioxymethylene catalyzed by CT175, a macroporous strongly acidic cation-exchange resin. The influences of reaction conditions such as catalyst types, reaction temperature, time, pressure, catalyst dosage, and mass ratio of DMM to trioxymethylene were also investigated. Under the optimized conditions of m(dimethoxymethane):m(trioxymethylene)=2.5:1, CT175 (7.5wt.%), 90 degrees C, 0.5h, and 1.5MPa, the conversion of trioxymethylene and the selectivity to PODE3-8 was obtained as high as 89.0% and 64.2%, respectively. Moreover, the resin catalyst can be reused up to 20 times without obvious change in its activity. The 100% atom efficiency, green reaction process, mild reaction conditions, as well as easy workup make the protocol advantageous and acceptable.