LAMOST DR6_v1 which is released to domestic users in March of 2019 consistes of two components: the low-resolution part and the medium-resolution part. We make analyses of the parameters of DR6_v1 for low-resolution and medium resolution data respectively, which are described in detail in the following.

The following diagrams show the distributions of errors of atmospherical parameters (T*eff*, logg, [Fe/H]) as well as rv in different SNR of r band (snr)) bins.

The following figures show the comparisons of atmospherical parameters (T*eff*, logg, [Fe/H]) as well as rv between DR6 low-resolution data and SDSS DR15. The mean values and the standard deviations of the differences are also plotted in the figures. For the parameters of logg, a branch is seen in the top-right panel. It could be explained by the inhomogeneous distribution of the atmospherical parameters in the ELODIE library. There are holes for giants in the ELODIE library, making the estimations of the initial guess for atmospherical parameters in the giant holes inaccurate.

These figures show the distributions of error of atmospherical parameters (T*eff*, logg, [Fe/H]) and rv for single-exposure spectra. The errors of rv have six values which are calculated from three different methods, and for each method there are the errors and calculated errors of rv. A more detailed description can be found in the document of Medium Resolution Data Description. The errors of parameters are divided into four groups according to the snr, represented by different colors. We can see that the scatters of atmospherical parameters in the bin of 0<snr<30 are obviously larger than other bins.

The following figures show the distributions of error of atmospherical parameters (T*eff*, logg, [Fe/H]) and rv for combined spectra. The errors of parameters are divided into four groups according to the snr, presented by different colors. The errors of the parameters of the combined spectra show the very similar distributions to those of the single-exposure spectra.

A comparisons of atmospherical parameters (T*eff*, logg, [Fe/H]) and vsini between DR6 Medium-resolution data and AOPGEE are shown in the following figures. Similarly, the comparisons contain two groups including the single-exposure (the first four figures) and combined spectra (the last four figures). We also plot the mean values and the standard deviations of the differences of the parameters in the figures.

The distribution of [α/Fe] of both dwarfs and giants for the single-exposure and combined spectra are respectively plotted in the following figures. For dwarfs, [α/Fe] is estimated by template matching with synthetic spectra, and for giants, [α/Fe] is estimated by the convolutional neural network (CNN) method. In each figure, the distribution of [α/Fe] of dwarfs is represented by blue and the distribution of [α/Fe] of giants is represented by green.