Based on the synthesis of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and ferrocene-1,1 '-dicarbaldehyde (FcDc), a variety of novel La3+-, Sb3+-doped MOF-In2S3@FcDc-TAPT COFs hybrid materials were designed and synthesized with NH2-MIL-68(In) as matrix. A dense cladding layer has formed on the surface of the MOF-In2S3 heterostructure through coating FcDc-TAPT COFs. The detection of C-N bonds confirmed that the hybrid materials were covalently bonded with the ferrocene-1,1 '-dicarbaldehyde (FcDc)-modified covalent triazine-based frameworks (FcDc-TAPT). Then, the photocatalytic reduction of Cr(VI) in aqueous phase under visible light was implemented with the hybrid materials as photocatalysts. Doping La3+ or Sb3+ has obviously improved the photocatalytic degradation efficiency of Cr(VI). In particular, Sb3+-doped MOF-In2S3@FcDc-TAPT COFs had the best removal of Cr(VI) with removal rate of 99% within 20 min. By fitting the experimental data with the pseudo-first-order equation, the speed constants were obtained. The kinetics constant of Sb3+-doped MOF-In2S3@FcDc-TAPT COFs for Cr(VI) degradation was 0.4307 min(-1), which was more than 19.87 times as much as that of the non-doped MOF-In2S3@FcDc-TAPT COFs hybrid materials. The DRS and PL results verified that the introduction of La3+ or Sb3+ into the hybrid materials could effectively inhibit the photogenic electron and promote the separation of electron-hole pairs. The cyclic and stability results displayed that the removal rate of Cr(VI) by Sb3+-doped MOF-In2S3@FcDc-TAPT COFs after five times of repeated use was still 95.39%; in particular, it was not significantly changed even after 150 d. It confirmed that the Sb3+-doped MOF-In2S3@FcDc-TAPT COFs was a very stable catalyst, due to the carbonyl and Cp ring conjugate of FcDc, which could produce delocalized electrons and stabilize the ions or free radicals.