An experiment was carried out during 2017-19 to study the morpho-physical and bio-chemical characters of Thai Apple ber (Ziziphus mauritiana Lamk.) grown in Assam. The leaves of Thai Apple ber fruits collected from different locations of Assam showed elliptic shape with serrate leaf margin, obtuse apex and oblique base. The colour of mature leaves was observed to be dark green. The leaf length, leaf breadth and petiole length of Thai Apple ber fruits shows a great variations among all collection. The plant of Gela Pukhuri and Simen Chapori recorded early flowering and harvesting among the Thai Apple ber plants of other locations in the present study. The fruits of Boitamari (BC-8) recorded longest fruit (5.10cm) while, maximum fruit weight (53.08g) was recorded in BC-1 (Simen Chapori). The shape and surface of seeds was found to be ovate and warty and pulp-stone ratio ranged from 18.76 -23.28.The biochemical analysis reveals that the quality characters like moisture content, TSS, titratable acidity, TSS-acid ratio and ascorbic acid content differed. Total sugar (6.37 -7.81%) and reducing sugar (2.44 -3.06%) contents varied significantly among the Thai Apple ber fruits of different locations. The highest vitamin A (16.08 μg/100g) were found in Gela Pukhuri (BC-3) and highest protein (0.87g/100g) was found in BC-2 (Bongalmora). The calcium and phosphorus contents of the Thai Apple ber fruits ranged from 20.48mg/100g to 23.50mg/100g and 24.08mg/100g to 25.25mg/100g, respectively. It can be concluded that Thai Apple apple ber fruits can successfully be grown under sub-tropical area of Assam. The ber fruits collected from Simen Chapori (BC-1) was found best in terms of biochemical composition i.e. TSS, TSS/ acid ratio, total sugar, reducing sugar and moisture content.