Abstract: In the present study, an arbuscular mycorrhizal fungus (AMF) strain Acaulospora spinosa XJ27, previously isolated from tomato root rhizosphere in Xinjiang’s suburbs, was used to inoculate root systems of tomato cultivar “MicroTom”. The biomass, contents of chlorophyll in leaves and lycopene in fruits of plants between the treatments with and without XJ27 were analyzed, and the expression level of lycopene biosynthesis relevant genes (psy1 and psy2) investigated by semi quantitativePCR and realtime PCR. The results indicated that the application of XJ27 to the rhizosphere of tomato increased the biomass and yield of the treated plants, the expression of psy1 and psy2 was improved, and the amount of lycopene accumulation in tomato. It suggested Acaulospora spinosa XJ27 has a great potential in utilization.