Abstract: To enhance the utilization of detoxified city sewage sludge, the effect of sewage sludge compound fertilizer on the growth of Poa annua Linn. and activity of soil enzyme were studied in a pot experiment. Results indicate dramatic enhancement of the activities of soil urease, protein enzyme and invertase with increasing rates of sewage sludge in compound fertilizer under consistent N, P, K amounts. At the same time, there is observable improvement in the color of grass, while the grass-cuttings and tillering number increase. And especially in the middle to late growth stages, grass color improves by two grades, weight of grass-cuttings increases by 10 ～ 15 g·pot^-1, tillering increases by 30 ～ 50 tillers per pot, while permeability of cell membrane reduces by 40%. However, if sewage sludge N nutrient goes above 60%, the sewage sludge fertilizer has very little effect on grass. Therefore, in using compound sewage sludge fertilizers, N nutrient should be kept within 60%.