The magnetic properties and magnetoresistance effect of Y1-xGdxMn6Sn6 (x=0-1) compounds have been investigated by magnetization and resistivity measurements in the applied field range (0-5 T). Compounds with x=0.4-1display ferrimagnetic behaviours in the whole magnetic ordering temperature range, while compounds with x=0-0.2display a field-induced metamagnetic transition, and the threshold fields decrease with increasing Gd content. The compounds with x=0.1-0.2 undergo an antiferromagnetic to ferromagnetic transition with increasing temperature. The cell-parameter a and c and cell-volume V of compounds (x=0-1) increase with increasing Gd content. It was found that the saturation magnetization Ms of the compounds (x=0.4-1) decreases, while the ordering points of the compounds (x=0-1)increase with increasing Gd content. A large MR effect was observed in the compound with x=0.2, and the maximum absolute value of MR at 5 K under 3 T is close to 19.3%.