Resistance　spot　welding　is　one　of　the　most　widely　used　processes　in　metal　fabrication,　but　the　expulsion　affects　the　spot　quality.　To　develop　a　precise　and　reliable　weld　quality　assessment　method　for　resistance　spot　welding,　the　welding　force　signal　was　measured　and　a　novel　wavelet　transform　based　on　multi　indexes　is　proposed.　The　impulse　and　resultant　damping　vibration　signal,　which　is　the　most　obvious　feature　of　expulsion,　was　extracted　from　the　welding　force　waveform　by　7-level　wavelet　transform　with　Daubechies5　wavelet.　The　detail　signal　in　level　6　was　chosen　as　the　target　signal,　as　it　covers　the　dominant　frequency　of　expulsion.　To　obtain　the　local　characteristics　of　the　expulsion,　a　multi　indexes　were　calculated　which　includes　the　peak-to-peak　value,　kurtosis　index,　and　pulse　index.　The　peak-to-peak　measures　the　range　of　a　signal　value,　and　kurtosis　index　and　pulse　index　are　sensitive　to　the　impulse　signal.　According　to　experimental　analysis,　the　peak-to-peak　value　of　the　expulsion　signal　is　significantly　higher　than　that　of　other　conditions,　while　other　two　indexes　are　not　that　obvious　but　with　same　trend.　The　experimental　data　results　show　that　the　multi　expulsion　indexes　are　effective　indicators　in　evaluating　expulsion　in　resistance　spot　welding.