Lap joints are necessary for making ultra-long laminated bamboo sliver lumber（LBSL）.Effects of the length and the position of lap joints were analyzed by testing the lumber’s bending and tensile strength.The results showed that the length and the position had significant influence on bending（MOE and MOR）and tensile strength（ts）.The length had no significant effect until it exceeded 10 mm.However,when the joints were at the surface of the lumber there was a negative influence on bending and tensile properties.It was concluded that the length of the joints should be longer than 10 mm and should not be at the surface of the lumber.