The invention discloses a lenticular balance beam enabling balance force to be uniformly distributed. The lenticular balance beam comprises horizontal rods, vertical rods, steel strands, enclosing purlin assemblies, fixing parts, splayed bracings, inverted-T-shaped parts and lenticular balance beam ends. The inverted-T-shaped parts are assembled on the two ends of the enclosing purlin assemblies in a connected mode, and the lenticular balance beam ends are fixedly arranged on the outer side ends of the inverted-T-shaped parts. The vertical rods are distributed on the tops of the enclosing purlin assemblies at intervals, and the direction of the vertical rods is perpendicular to the extension direction of the enclosing purlin assemblies. The horizontal rods are connected between the adjacent vertical rods. One ends of the fixing parts are adjacent to the vertical rods, and the other ends of the fixing parts are adjacent to the horizontal rods. The splayed bracings are connected between the bottoms of the vertical rods and the enclosing purlin assemblies. The steel strands are arranged at the top ends of the vertical rods in a striding mode, and the two ends of the steel strands are connected to the lenticular balance beam ends in an anchored mode. The invention further discloses a design method of the lenticular balance beam enabling the balance force to be uniformly distributed. According to the lenticular balance beam enabling the balance force to be uniformly distributed and the design method thereof, the tension of the steel strands can be uniformly transmitted to the enclosing purlin assemblies, and uniform resistance can be provided for resisting the soil pressure of a foundation pit.