This paper explores the possibility of realizing the CSMA mechanism in a large indoor optical internet of things environment.We abstract indoor nodes using diffuse reflection light to complete carrier sense process into the choice problem of independent sets based on stochastic theory,which models the process of random access of commun ication nodes based on hard core point process (HCPP).We derive the relational expression between carrier-sensi ng threshold and the intensity of simultaneous active transmitters.We analyze how possion point proce ss(PPP)node density,carrier-sensing threshold and the emission angle of LED light source affected the intensity of s imultaneous active transmitters.The results show the existence of an optimal carrier-sensing threshold for a give n emission angle which maximizes the intensity of simultaneous active transmitters.