The transmission spectra of p-PbTe have been measured by the strip-line technique with different far infrared laser wavelengths at different anhgles of the direction of maqnetic field relative to the crystal axis at low temperature of 1.5 k. A strong influence of mode coupling on strip-line transmission spectra has been observed and analyzed. The final results extracted from experimental spectra by numerical simulation are in good agreement with the six band k·p model calculation.