A spilt plot design field experiment was conducted at Ibshway, Fayoum governorate, Egypt 2017 to study the effect of two sources water (fish culture water and Nile water) and nitrogen levels fertilizer on biodiversity of Spider and other arthropods, also, its effect on yield and protein of cowpea. Community composition of collected spider was determined throughout the period of study using the Shannon-Wiener and Simpson Indices of diversity. A total of 394 individuals (228 fish cultural water and 166 Nile fresh water) represented by 10 families of 19 identified genera, of higher diversity index in fish culture water system. According to Simpson, it was found that Fish culture water system included the highest number of dominant species. Family Lycosidae recorded the highest number of spiders where 170 individuals with two egg sac and 123 individuals with two egg sac of fish culture water system and Nile freshwater system respectively. Sørensen Quotient of Similarity between Fish culture water system and Nile fresh water system are nearly approximate, as they recorded 64 % of similarity by 81.25%. Other Arthropods were represented by 23 species belonging to 16 identified families, 7 unidentified families, and 12 orders. A total of 2832 individuals in fish culture water system and 2169 individuals in Nile freshwater system were counted from 9 observations on cowpea from seedling to maturity by using pitfall trap. A total of 471 individuals in fish culture water system and 592 individuals in Nile freshwater system by using Leaves. Statistical analysis for spider, soil fauna and pests on leaves proved that no significant differences were observed between Fish culture water and Nile water but significant differences in yield and protein. Nitrogen levels were no significant differences in spider and soil fauna but significant differences in pests on leaves, yield and protein. Interaction between water sources and Nitrogen levels were no significant differences in spider but significant differences in soil fauna, pests on leaves, yield and protein.