This paper presents results of studies on the composition and quantity dynamics of nektonic invertebrates in Jiaozhou Bay and adjacent waters using materials including 78 nektonic invertebrate species collected in May and August, 1986-1995. Mollusca 33 species, Crustacea 27 species, Echinodermata 10 species and 8 other species. The average density in August and May were 207×103 ind /k㎡ and 54×103 ind/k㎡ respectively. The maximum density (594×103ind. /k㎡)occurred in August，1990 and the minimum(24×103ind./k㎡) in May1995.The average stock biomass were 881 tons in August and 363 tons in May. The stock biomass maximum (1614 tons) occurred in August, 1990 and the minimum (56 tons)in May 1995. The ecological features and quantity dynamics of Loligo japonica, Loligo beka,Sepiella maindroni, Sepia esculenta, Octopus ocellatus, Octopus variabilis, Portunus trituberculatus,Charybdis japonica, Oratosquilla oratoria, Metapenaeus joyneri and Trachypeneus curvirostris are described.