A \(\text{signed\,graph}\) (or \(\text{sigraph}\) in short) \(S\) is a graph \(G\) in which each edge \(x\) carries a value \(s(x) \in \{+1, -1\}\) called its \(sign\) denoted specially as \(S = (G, s)\). A sigraph \(S\) is \(\text{sign-compatible}\) if there exists a marking \(\mu \) of its vertices such that the end vertices of every negative edge receive ‘-’ signs in \(\mu \) and no positive edge in \(S\) has both of its ends assigned ‘-’ sign in \(\mu \). In this paper, we write algorithms to detect sign-compatibility of a given sigraph and obtain optimal algorithm with complexity \(O(n^2)\).