Choosing the TP347H steel which is used for the boiler heating surface in the thermal power plants as a research object, the characteristic of plasma spectral of the samples with different surface states(the unground and the ground) was analyzed. The experiment results show that, the change trends of the acquired spectral data of the two surface states are great difference with the increase of the laser hitting times. For the unground samples, the characteristic spectral line of Ca can clearly be detected in the whole experiment process. For the ground samples, the characteristic spectral line of Ca only exists in the beginning. For the unground TP347H samples containing of the elements of Fe and Mn, the absolute spectral intensity increases rapidly then reduces with the increase of the laser hitting times. For the ground TP347H samples, the absolute spectral intensity increases rapidly firstly then keeps relatively stable within a certain range with the increase of the laser hitting times. The unground samples exists fouling and slagging on the surface, which can enhance the spectral intensity, plasma temperature and electron density in a certain extent. But the spectral data stability of ground partis is better than that of the ground samples.