Symbolic execution is a frequently used method for vulnerability detection in smart contracts. However, existing tools face limitations with the \textit{constraint solving} and may cause the \textit{``path explosion''} problem. This costs too much time and may lead to False-Negative (FN) of detection results. In this work, we propose \textit{\textbf{ParSE}}, a novel approach that leverages \textit{\textbf{Par}allel} and \textit{\textbf{S}implified} symbolic \textit{\textbf{E}xecution} to improve both detection efficiency and the number of True-Positive (TP). We inject ParSE into two widely used symbolic execution tools, Oyente and Mythril, for detecting vulnerabilities in smart contracts. Experimental results show that ParSE accelerates to \textbf{9.33x} and \textbf{5.30x} for Oyente and Mythril, respectively. Moreover, tools based on ParSE improve the detection number of TP.