In order to acquire more compact form of PAM (Pulse Amplitude Modulation) decomposition of Multi-hCPM (Continuous Phase Modulation) signals, a novel algorithm to represent Multi-h CPM signals through a finite-state sequential machine (SM) is presented. In this algorithm, based on the periodically varying modulation index,Multi-h CPM signals are represented as the cascade of a periodically time-invariant (PTI) finite-state SM and abank of PTI PAM modulator via the basic waveform decomposition. Then, the state transition process is describedas a reducible and cyclostationary non-homogenous Markov chain by defining even input alphabet ary. The processof state transition with different modulation indexes is validated through some examples, and the model of optimal re-ceiver as well as the simulation results is presented. As compared with the conventional optimal detection algorithmbased on PAM decomposition, the proposed algorithm attains the theoretical detection performance with half numberof trellis.