The aim of this research are to analyze the impact of declining tick size toward stock liquidity and changes of order strategy. Relative bid ask spread and bid ask depth were used for analyzing stock liquidity. Whether Marketable Limit Order to Total Order was maintained to analyze the changes of order strategy. The result implies that relative spread decrease after tick size declining policy and stock more liquid. But, declining of depth can not raise tock liquidity. Comparation between depth and relative spread was maintained for solving opposite results of soread. The finding is there is no significant of liquidity. deterioration of relative spread result in cheaper cost of transaction and stock execution faster than before. Therefore traders are able to change strategy from limit order to market order.