Background The development of new adjuvants for human use has been the focus of attention. This study’s aim is to explore the possibility of using nanoparticle Ca nanoparticles (CA) as a vaccine adjuvant of anti-idiotypic antibody NP30 against schistosomiasis and its protective mechanisms. Methods Nanoparticle CA-NP30 conjugate (CA-NP30) was fabricated. BALB/c mice were immunized actively with CA-NP30 to evaluate its effects of protective immunity on mice. The serum levels of specific IgG,IgG1 and IgG2a antibodies against NP30 and the concentrations of IFN-γ and IL-4 in supernatant of splenocytes were determined via ELISA. Results Nanoparticle CA could enhance significantly the protective immunity of NP30 against infection of Schistosoma japonicum and the worm reduction rose from 36.0% (NP30 alone) to 52.6%. The serum levels of specific IgG,IgG1 and IgG2a antibodies against NP30 increased remarkably,as compared with those of the group immunized with NP30 alone. The concentration of IFN-γ in supernatant of splenocyte was drastically elevated [the groups immunized with CA-NP30 and NP30 alone were (493.80±400.74) pg/ml and (39.03±39.58) pg/ml,respectively],but the concentration of IL-4 showed no significant difference from that of NP30 alone [(27.94±9.84) pg/ml vs (27.28±14.44) pg/ml]. Conclusions Nanoparticle CA could act as a vaccine adjuvant of anti-idiotypic antibody NP30 against schistosomiasis. The mechanism could be that CA-NP30 enhances humoral and cellular immune responses in mice. Background The development of new adjuvants for human use has been focused on attention. This study’s aim is to explore the possibility of using nanoparticle Ca nanoparticles (CA) as a vaccine adjuvant of anti-idiotypic antibody NP30 against schistosomiasis and its protective mechanisms. Methods BALB / c mice were immunized actively with CA-NP30 to evaluate its effects of protective immunity on mice. The serum levels of specific IgG, IgG1 and IgG2a antibodies against NP30 and the concentration of Nanoparticle CA could enhance the protective immunity of NP30 against infection of Schistosoma japonicum and the worm reduction rose from 36.0% (NP30 alone) to 52.6%. The serum levels of specific IgG, IgG1 and IgG2a antibodies against remarkably increased NP30, as compared with those of the group immunized with NP30 alone. The concent ration of IFN-γ in supernatant of splenocyte was drastically elevated [the groups immunized with CA-NP30 and NP30 alone were (493.80 ± 400.74) pg / ml and (39.03 ± 39.58) pg / ml, -4 showed no significant difference from that of NP30 alone [(27.94 ± 9.84) pg / ml vs (27.28 ± 14.44) pg / ml]. Conclusions Nanoparticle CA could act as a vaccine adjuvant of anti-idiotypic antibody NP30 against schistosomiasis. mechanism could be that CA-NP30 enhances humoral and cellular immune responses in mice.