An optically thin gaseous mixture of Cs and Na is excited by the CW dye laser, the laser frequency v is tuned in the wings of the Na resonance transitions. The excited NaCs molecule is predissociated into the Na3P1/2 or 3P3/2. The branching ratio is defined as 7(D1)/I(D2) where I(D1) and I(D2) are measured intensities of the atomic NaD1 and D2 lines. The branching is determined in the Cs density range 2 to 8 × 1014cm-3. The ratio is measured for detuning ranging from about 300 cm-1 in the blue wing to 100 cm-1 in the red wing of the Na3P multiplet. The ratio of dissociation rates and the fine structure changing cross section are obtained. The branching is found to be strongly detuning dependent in the vicinity of the NaCs near-wing satellites. Fine structure changing cross section has also been measured for resonant excitation of Na3~2PJ state. The results are discussed.