The field experiment on Influence of Vermicompost and PSB on growth and carboxylation efficiency of custard apple (Annona squamosa L.) cv. Raidurg was carried out at Fruit Research Farm, Department of Fruit Science at College of Horticulture and Forestry, Jhalawar (Rajasthan) during study period from October 2014 to April 2015. The experiment consisted of different doses of Vermicompost (2kg/plant, 4kg/plant and 6kg/plant) along with PSB (25g/plant, 50g/plant and 75g/plant) and its combination. The results revealed positive correlation of photosynthesis with increase in no. of shoots/branch; increase in canopy volume and percentage increase of scion girth under interactive effect of Vermicompost @ 6kg + PSB 75g/plant .The result showed that maximum per cent increase in East-West (18.22%), North-South spread (17.83%), plant height (18.34%), canopy volume (34.50%), leaf length (29.36%) as well as leaf width (25.77%), increased number of shoots (15.78), scion girth (8.28%), rootstock girth (8.51%) and relative water content (73.71%) were recorded under T₁₅ treatment i.e. Vermicompost@ 6kg + PSB 75g/plant. The carboxylation efficiency parameters were also observed maximum in respect of photosynthetic rate(5.60μmol CO₂m^-2s^-1), photosynthetic active radiation (1608.33mmol m^-2s^-1), stomatal conductance (14.67 mmol m^-2s-¹), leaf temperature (38.13°C), relative humidity (5.84%), internal CO2 concentration (284.67ppm), transpiration rate (1.33 mmol m^-2 s^-1), and minimum vapour pressure deficit (47.80 mb) were noted under T₁₅ treatment (Vermicompost 6kg + PSB 75g/plant).