Plasma density fluctuation profile measurement is an important task in fusion plasma confinement. It is necessary in physics research that the fluctuation density signal be decomposed from the density signal accurately. Recently, a new technique, the wavelet and correlation technique, was utilized in computing the density fluctuation on the HL-2A tokamak for the first time. The db5 wavelet basis belonging to the orthogonal Daubechies wavelet was chosen for density signal decomposition and reconstruction. Two diagnostics supported this work: an 18-position magnetic coil array and a newly developed multi-channel far infrared interferometer system. During ohmic heating and electron cyclotron resonance heating discharge, density fluctuation is correlated with magnetohydrodynamics by correlation analysis; one can reduce the mode m = 2 or 1, n = 1 to its elements. From Abel inversion, the conclusion shows that the fluctuation distribution is strongly peaked at the edge, and the line-integrated fluctuation profile is slightly hollow.