Based on tunable diode laser absorption spectroscopy (TDLAS) technology, combining a Herriot cell with optical length of 50 m, using a wave-length-meter to scale the positions of the lines, the positions and intensities of 71 ethane lines between 6039 cm[EQUATION] and 6054 cm[EQUATION] are precisely measured, and the minimum detection absorption intensity reaches 10[EQUATION] cm[EQUATION]/(molecule[EQUATION]cm[EQUATION]). Results and errors are analyzed in detail, which is very useful to carry on research of natural gas in further.