Three sediment cores were extracted from Maigang Reservoir, located in the southwest of Guizhou Province, China. Ferrimagnetic minerals are the main magnetic minerals of the sediments. There are also other magnetic minerals, for instance, antiferromagnetic component. Super-paramagnetic grains were widely observed in the sediments. There is no significant relationship between mineral magnetic parameters, _χlf, _χfd, SOFT and textural parameters. Mineral magnetic parameters, _χARM, SIRM, F₃₀₀ is correlated with textural parameters but with low correlation coefficients; Given the significant correlations between _χARM/_χlf, _χARM/SIRM and textural parameters, _χARM/_χlf, and _χARM/SIRM can be used as a proxy of particle size. Results presented here do indicate that mineral magnetic parameters can be used as a particle size proxy. These data and other studies on different environments demonstrate that the relationship between mineral magnetic parameters and textual properties can vary from different sedimentary environments even in the same overall sedimentary system, and in some circumstances, mineral magnetic parameters are not suitable to be particle size proxy. To employ magnetic characteristics as a particle size proxy, the mechanism behind the relationship between magnetic parameters and particle size should be explored fully for each sedimentary environment.