Immunotherapy is expected to become an promising strategy in inhibiting tumor postoperative recurrence and metastasis. However, the effect is still unsatisfactory because of lacking cooperativity between various therapeutic methods. In this study, we designed an efficient synergistic immunotherapy system as an all-around and multi-dimension method for inhibiting tumor postoperative recurrence and metastasis. The efficient synergy lay in enhancing immune effect and eliminating immune suppression in the meantime by took advantages of CpG oligodeoxynucleotides (CpG ODNs) and antiPDL1 antibody. We introduced nanomaterials based on the calcium alginate hydrogel which has an acknowledged biological safety to implement the above strategy and make the system multifunctional. This nanosysterm have both therapy function and long-term monitoring capability in vivo to evaluate the recurrence and metastasis situation of postoperative residual tumor cells conveniently in real time. In vitro and vivo results proved that that this system could achieve a much better tumor inhibition efficiency and a good monitoring effect. This efficient synergistic immunotherapy nanosystem is expected to become a new promising strategy for postoperative immunotherapy of tumor.