By Hall's marriage theorem, we study lower bounds of the Lin-Lu-Yau curvature of amply regular graphs with girth 3 or 4 under different parameter restrictions. As a consequence, we derive that the Lin-Lu-Yau curvature of any strongly regular conference graph with parameterIn general, it is still open whether the Lin-Lu-Yau curvature of an amply regular graph of parameter (n, d, α, β) with girth 3 (i.e., α ≥ 1) and β ≥ 2 is always nonnegative or not. Our approach also provides a geometric proof of a classical diameter estimates of amply regular graphs in the case of girth 4 and some special cases of girth 3.