Thin films of SnO

2

can be prepared in a highly conductive form with the important properly of being highly transparent in the visible and near-IR regions of the solar spectrum. Potential applications of the thin film are coatings in heat minor systems as well as in solat cell technology. In this paper

we report the effect of annealing temperature on the photoluminescence of SnO

2

films. Experimental samples were made by the spraying method that involves the decomposition at high temperature (around 500℃) of a mineral compound such as SnCl

4

5H

2

O dissolved in a solution of water and alcohol. Water is used here as an oxidizing agent.Experimental results show that the annealing process has a significant effect on the photoluminescence of SnO

2

films. The influence is very different in oxygen and nitrogen. A "red shift" of the peaks of photoluminescence appeals when samples are annealed in O

2

atmosphere at 300-500℃

while the emission peaks of annealing samples in N

2

or H

2

exhibit a "blue shift". The change of emission peaks of the SnO

2

films may be attributed to the change of oxygen vacancies in SnO

2

films during annealing. Undoped tin oxide films have

n

-type extrinsic conduction. The Sn

2+

ions

associated with the oxygen vacancies

and the residual Cl

-

ions are both capable of being electronic donors and probably both are responsible for this extrinsic conduction. The free carrier concentration of the conduction band changes with changing oxygen vacancies after annealing in oxygen or nitrogen. The change of the earlier concentration causes the change of optical gap energy according to Bursein effect.The peaks of photolumine-scence are then shifted with the change of optical gap energy after heat-treatment.