The depletion of traditional energy leads to increasing demand on renewable energy. Among various forms of renewable energy, the solar panel are gaining importance and growing rapidly. Potovoltaic system performance affected by partial shading which due to near buildings, poles, passing clouds, fallen leaves, etc. Partial shading cause reduction in the power output and consequently, reduces the efficiency. This paper investigates the effect of various cases of partial shading (vertical string, horizontal string and single cell) at environmental condition on the current voltage and power voltage characteristics of photovoltaic panel which have in 88W power. The experiments were done for various parameters such as shading positions and ratio. The results showed that at 100% shading condition, the maximum power dropped by99.36, 43.7 and 41.15% for horizontal, cellular and vertical shading at the same solar radiation level in compared with their initial state value.