An apparatus and a method for detecting traffic channel signal transmission in a rake receiver may advantageously ensure stable and accurate detection performance in performing continuous/discontinuous transmission detection of traffic channels with a rake receiver in a mobile communication system based upon CDMA 2000 standards by making sufficiently spaced distribution in traffic channel signal-to-noise ratios estimated in continuous/discontinuous transmission. The method includes compensating traffic channel signals according to fingers, respectively, by using estimated pilot channel signals; combining the compensated finger-based traffic channel signals and estimating signal-to-noise ratios for traffic channels; and comparing the estimated signal-to-noise ratios with a preset threshold value, respectively, to detect continuous or discontinuous transmission of the traffic channels based upon comparison results.