In order to investigate and compare the distribution characteristics of the spatial complexity of the lake water ions, the sliding sample entropy and spatial interpolation are employed in this study. The three hundred and thirteen sampling sites in one hundred and fifteen lakes are divided into two groups(one group includes September 2009 and September 2010, another group includes April 2011, April 2012, April 2013 and April 2016) to calculate entropy and analyze spatial complexity. The results show that the spatial complexity of each ion and TDS in April is larger than that in September. The correlation coefficients between the entropy values of TDS and Na⁺, Cl^- and K⁺ are rather high in both April and September. The variation trend of spatial complexity of TDS is consistent with that of Na⁺, Cl^- and K⁺. In September and April, the spatial complexities of Na⁺, Cl^-, K⁺, CO₃^2- and HCO₃^- are high in the northwest and southeast corner, but low elsewhere. The ion of Mg²⁺ has less complexity than other ions in the same month, but has higher complexity in the middle part of the sampling RegionⅠ. The spatial complexity of Mg²⁺ and Ca²⁺ is quite different in September and April. Ca²⁺ has a mutation high interval of ion complexity in the northwestward of sampling RegionⅠ in September compared with the lows value of ion complexity outside the interval. The spatial complexity trend of SO₄^2- is almost the same in April and September; while there is no high values of entropy in the southeast corner. Climate condition is the dominant factor for the seasonal variation of ion's entropy. In the same month with the same climate conditions, the water source recharge is the main factor affecting the spatial variation of entropy of the soluble ions. In April and September, the low entropy values of soluble ions in the middle of the study area indicate that there exists large water supply.