Abstract: There is a highly complex interaction relationship between the fungi, and then because of the changes in the number of the species of the dendrocola mycoflora, the influence of the change on the nematode-trapping fungi have been in changing. Experimental results show that , no matter whether carrying out the duel culture between A. oligospora and Pestalotiopsisa , A. oligospora and Trichoderma, A. oligospora and Verticillium, or among A. oligospora、Verticillium and Pestalotiopsisa, the growth of A. oligospora is all inhibited. Therefore the above four pairs all have the lower biocontrol value. But when carring out the dual culture among A. oligospora、Trichoderma and Pestalotiopsisa, in most of the time, the growth of A. oligospora is always promoted, when carring out the dual culture between A. oligospora and Verticillium, in some periods, the growth of A. oligospora could be promoted. Therefore, the above two pairs should be able considered to be used in biological control, but the most important thing is to accurately grasp the opportunity.