In order to study the economic threshold of cereal cyst nematode (CCN), formulate the prevention and control countermeasure. Effects of population density of CCN on agronomic characteristics and yield losses of spring wheat were evaluated in greenhouse and field experiments, and the regression equation on correlation between CCN population density and yield losses was established. The results showed that damage of CCN to wheat roots could remarkably affected wheat agronomic characteristic including root development, wheat plant height, number of tillering and spikelets, and 1000-grain weight. The infulence of CCN to the tested agronomic characteristic was not significant different and yield losses were less than ten percent when population density of CCN was less than (15±2.5) eggs/g soil, while the agronomic characteristics test were significantly decreased and the yield losses were between 15.52% and 55.01% when the density of CCN was more than (30±3) eggs/g soil. We should strengthen the prevention and treatment to CCN in area the population density of CCN was more than 30 eggs/g soil.