In order to fulfill the demand of more application scenarios, the current light water reactor core design is becoming complicated and compact. The Helical Cruciform Fuel (HCF) has attracted wide attention because of its superior thermal performance and stability structure. Considering the complex geometry and neutronics spectrum, neutronics analysis based on determinism is of lower precision and poor applicability since it involves a lot of theoretical approximations. However, the full-core neutronics analysis based on Monte-Carlo is very resource-intensive and low efficiency. In order to simultaneously enhance the computational accuracy and efficiency of neutronics analysis, this paper employs a Monte Carlo homogenization coupled with multi-group diffusion technique to analyze a complex core loaded with helical cruciform fuel assemblies. The study demonstrates that the current Monte Carlo-deterministic coupling method exhibits satisfactory accuracy across various control rod insertion scenarios within the complex core.