Abstract: When the seismic wavelet has little temporal and spatial changes, single reservoir time thickeness is much more than 1/4λ, and the wave impedance′s change of caprock is not large, we can get a positive correlation formula between seismic amplitude and P?wave impedance through the convolution model′s derivation. This paper makes a more detailed subdivision to composite volcanic rocks and the lithology distribution prediction in Dixi?14 well area in Kelameili gas field by combining with the seismic attributes such as amplitute, frequency, waveform, as well as the reflection time to the top of the Carboniferous in longitudinal. Dixi?14 well area′s reservoir belongs to Carboniferous volcanic rocks dominated by volcanic breccia and tuff, which is mainly effusive basalt and rhyolite in the rim and tuffaceous sandy conglomerate in the middle. With the wave impedance becoming larger, from tuffaceous sandy conglomerate to volcanic breccia, tuff, and then rhyolite, dacite or basalt, the seismic amplitudes enhance successively. The study suggests that there may exist many craters in the area, which include positive structure and negative structure like caldera. In the same way, this paper develops the volcanic spatial eruption modle for Kelameili gas field