CrI3 monolayer has attracted much attention, but it holds a very low magnetic stability, with Curie temperature (TC) of 45 K, seriously limiting the practical applications. To find solutions for this issue, we construct CrI3/As vdW heterstructures (vdWHs). Calculations show that such vdWHs are half-semiconductor with excellent mechanical property and TC of 75.9 K, improved by 73.3 % compared with CrI3 monolayer. Due to a weak orbital hybridization and coupling occurring between As layer and Iin atom-layer upon vdW interactions, the potential well of interfacial Iin atom-layer would become shallower, which make electron flow out from Iin atoms and magnetic moments increased for Cr and Iin atoms, in turn, the ferromagnetic (FM) coupling in Cr-Iin-Cr superexchange magnetic coupling channel is strengthened. Particularly, the magnetic stability can be significantly raised by compression strain, leading TC up to 111.3 K, which is caused by super-exchange interactions of both Cr-Iin-Cr and Cr-As-Cr channels, and magnetic proximity effects increased further. For light absorption, the red-shifted absorption edge relative to CrI3 monolayer and high absorption peak appearing in visible and infrared region allow heterstructures absorbing solar energy in a wider range. Such a phenomenon can be further strengthened by compression strain.