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Based on the data release of the Large Sky Area Multi-Object FiberSpectroscopic Telescope survey (LAMOST DR5) and the \emph{Gaia} Early DataRelease 3 (\emph{Gaia} EDR3), we construct a sample containing 46,109 giant(log~$\emph{g}$ $\leqslant$ 3.5\,dex) stars with heliocentric distance d$\leqslant$ 4 kpc, and the sample is further divided into two groups of theinner ({\RGC} $<$ 8.34 \,kpc) and outer region ({\RGC} $>$ 8.34\,kpc). The{\LZ} distributions of our program stars in the panels with different [Fe/H]and [$\alpha$/Fe] suggest that the thick-disk consists of two distinctcomponents with different chemical compositions and kinematic properties. Forthe inner region, the metal-weak thick disk (MWTD) contributes significantlywhen [$\alpha$/Fe] $>+$0.2\,dex and [Fe/H] $<-$0.8\,dex, while the canonicalthick-disk (TD) dominates when [Fe/H]$>-$0.8\,dex. However, MWTD clearlyappears only when [$\alpha$/Fe] $>+$0.2\,dex and [Fe/H] $<-$1.2\,dex for theouter region, and its proportion is lower than that of the inner region withinthe same metallicity. Similar result can be obtained from the {\VP}distribution. The high fraction of MWTD in the inner than that in the outerregion imply that MWTD may form in the inner disk, and is an observationalevidence about the inside-out disk formation scenario.

Search for the metal-weak thick disk from the LAMOST DR5