The non-stoichiometric spinel Zn-Cr-Al oxide (ZCA-1.25) was prepared by co-precipitation method in order to develop a high activity and high yield bifunctional catalyst for synthesis of light olefin from syngas (STO), and its texture, crystal structure, morphology and surface charge properties were investigated. The results show that the addition of excessive zinc promotes the reduction of crystal grain size and the increase of surface oxygen vacancies. The zinc content is suitable when the Zn/(Cr+Al) mole ratio is 1.25, with high specific surface area and abundant oxygen vacancies, which is combined with SAPO-34 zeolite molecular sieve as a bifunctional catalyst to evaluate the catalytic performance of STO reaction directly. Under the reaction conditions of inlet n(H2):n(CO)=2:1, 3000 mL/(gcat·h), 3.2 MPa, 400 ℃, the CO conversion of 46.9% was achieved, and the light olefin yield was as high as 15.9%, higher than most of the existing literature reports (8~12%), especially the selectivity of by-product CO2 was only 29.2%, lower than the commonly reported 40~50% CO2 selectivity. It also provides an insight into inhibiting CO2 selectivity to improve the yield of target products. In addition, the catalyst has good activity and no carbon deposition after running for 100 h, therefore the stable catalytic performance makes it have the potential for industrial application.