Co-existence probability of antibiotics and heavy metals in soil environment increased with the large-scale development of feed and livestock industry. In order to analyze the effects of antibiotics and heavy metals on soil microorganism ecosystem, we studied the single or combined pollution of oxytetracycline(OTC) and cadmium(Cd) on soil respiration and enzyme activities by laboratory cultivation. The results showed that the soil respiration was inhibited firstly, and then stimulated by sole treatment of 10 mg/kg Cd, while activities of invertase, urease and phosphatase in soil were significantly inhibited during the whole process. The order of inhibiting rate for enzyme activity was invertase >phosphatase >urease. Soil respiration was significantly activated by sole treatment of OTC at concentration of 1 mg/kg, while inhibited first, then activated by OTC at concentration of 50 or 200 mg/kg. Activities of invertase and urease were inhibited but the activities of phosphatase fluctuated when oxytetracycline was solely used. The combined pollution treatments of OTC+Cd(1+10 mg/kg) as well as OTC+Cd(200+10 mg/kg) showed antagonistic action, while the treatment of OTC+Cd(50+10 mg/kg) presented synergistic action on soil respiration and the 3 kinds of enzyme activities. Soil respiration responded more sensitively than soil enzyme activity by combined pollution of OTC and Cd, with the maximum inhibition and activation rates of 98.98% and 300.82%, respectively. Effects of OTC and Cd on enzyme activities were less than that on soil respiration.