A group-theory analysis of single crystal LAP has been made. LAP belongs to monoolinio system with space group P2, its total 222 eigen-modes are classified: Γ = 111A+111B. The polarized Raman spectra and reflected in rared spectra of LAP and DLAP have been recorded in the range of 50-3700 cm-1. The spectra lines have been assigned to different atomic groups and the oompariflion of PO43- NH3+ and COO- groups in LAP and DLAP have been made. The experimental results confirms that the symmetry of DLAP is the same as that of LAP and deuterium broadens the region oi transparent.