We present LAMOST data on 168 gamma Doradus (gamma Dor) pulsating stars including stellar atmospheric parameters of 137 variables and spectral types for all of the samples. The distributions of period (P), temperature (T), gravitational acceleration (log(g)) and metallicity [Fe/H] are shown. It is found that most gamma Dor variables are main-sequence stars with early F spectral types and temperatures from 6880 K to 7280 K. They are slightly more metal poor than the Sun with a metallicity range from -0. 4 to 0. On the H-R and log g - T diagrams, both the gamma Dor and delta Scuti (delta Sct) stars occupy in the same region and some are beyond the borders predicted by current stellar pulsation theories. It is discovered that the physical properties of gamma Dor stars are similar to those of long-period delta Sct (P > 0. 3 d) stars. The stellar atmospheric parameters are all correlated with the pulsation period for short-period delta Sct variables (P < 0. 3 d), but there are no such relations for gamma Dor or long-period delta Sct stars. These results reveal that gamma Dor and long-period delta Sct are the same group of pulsating stars and they are different from short-period delta Sct variables. Meanwhile, 33 gamma Dor stars are identified as candidates of binary or multiple systems.