Metal smelting process all kinds of element content directly influence the metal performance index and smelting process control .The amount of carbon become mainly alloy index for divided type and number. LIPS using high power laser ablation material produce plasma, in plasma radiation spectrum analysis; it could be used in the composition of solid, liquid and gas composition and concentration measurement. But the results of the measurement will be affected by some factors, this article through some experiments, that show the Influence factors for the measured results such as the delay time,the different environment of gas and the laser pulse energy and analyzed them.