Bamboo composite is a kind of engineering composite bamboo with modern processing technology, high strength and quality ratio, environmental protection and beautiful appearance. In order to study the influence of shear-span ratio on the shear capacity of side-loaded bamboo-integrated beams, five groups of three beams in each group with shear-span ratio of 0.75, 1.0, 1.5, 2.0 and 2.5 were designed to carry out four-point bending tests. The deformation characteristics, failure modes and the influence of shear-span ratio of side-loaded bamboo-integrated beams were studied. The influencing factors of shear performance and the calculation method of bearing capacity of bamboo composite beams were studied. The results show that the bamboo composite beams have higher bearing capacity and stiffness, and the shear capacity is related to the ratio of shear span. When the shear span ratio is less than 1.5, interlaminar shear failure occurs, while when the shear span ratio is greater than or equal to 1.5, bending failure occurs. The formulas for calculating the flexural bearing capacity, shear bearing capacity and elastic deformation of bamboo composite beams are put forward, which is in good agreement with the measured values.