Effect of divalent dopants, Zn2+ ion, on the high-order photon avalanche(PA) upconversion(UC) emission of Er3+ doped Bi OCl microcrystals was investigated. XRD results indicated that Zn2+ ion dopants would mostly enter into the lattice space at low and moderate doping concentration, and began to substitute Bi3+ ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3+ ions could be observed, and the UC emission intensity increased with increasing the Zn2+ addition below 8 mol.%, then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2+ had no obviously negative effect on the occurrence of PA emission. On the bases of results investigated herein, we considered that the lattice distortion by Zn2+ doping could not directly change the special PA emission of Bi OCl:Er3+, but would improve the emission intensity when used as lattice modifier. Effect of divalent dopants, Zn2 + ion, on the high-order photon avalanche (PA) upconversion (UC) emission of Er3 + doped Bi OCl microcrystals was investigated. XRD results indicated that Zn2 + ion dopants would mostly enter the lattice space at low and moderate doping concentration, and began to substitute Bi3 + ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3 + ions could be observed, and the UC emission intensity increased with increasing the Zn2 + addition below 8 mol.%, Then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2 + had no obviously negative effect on the occurrence of PA emission. On the bases of results before herein, we considered that the lattice distortion by Zn2 + doping could not directly change the special PA emission of Bi OCl: Er3 +, but would improve the emission intensity when used as lattice modifier.