In order to study soil characteristics,microorganism,diseases and pests in protected continuous cropping of tomato,soil samples of cultivating tomato for 1,3,5 and 8 years were collected and their chemical and physical characteristics and amount of microorganism determined.At the same time,diseases and pests of tomato in these lands were recorded.The results showed that as continuous cropping lasted,soil pH and unit weight decreased,soil electric conductance and organic content increased.Soil available N,P and K increased at first,then available P and K decreased slowly,but available N increased continuously.A mount of bacteria and acti nomyces increased at fi rst and then decreased,whereas amount of fungi i ncreased conti nuously and it was 183.79% of that of control in continuous cropping of 8 years.According to eval uati on of integrated diseases resistance at the end of production season,diseases susceptible increased continuously.Root knot nematode occurrence also showed a same change style.