In order to study the correlation between bearing capacity of helical piles in sand foundation and oblique tensile angle and burial depth, the finite element model of helical piles in sand is established by ABAQUS. The numerical simulation results and test results of helical piles under vertical and horizontal pull-out are compared to verify the accuracy and feasibility of the numerical model. Considering the influence of oblique tensile angle and burial depth on the ultimate bearing capacity of helical piles, four groups of helical pile models with different burial depths, are set up and different oblique tensile angles are applied respectively. The results suggest that the ultimate bearing capacity of helical piles in sand decreases when the oblique tensile angle increases. When the oblique tensile angle is less than 30°, the relationship curve between the ultimate bearing capacity and the oblique tensile angle is approximately linear. There is a critical burial depth ratio for the ultimate bearing capacity of helical piles. When the burial depth ratio is not less than 4, it does not change with the increase of burial depth ratio. Meanwhile, the ultimate bearing capacity formula of deeply buried helical piles under oblique tensile load is derived. Through verification, the formula can better reflect the rule that the ultimate bearing capacity of helical piles decreases gradually with the increase of oblique tensile angle.