  Motivated by the recent progress of direct search for the productions of stop
pair and sbottom pair at the LHC, we examine the constraints of the search
results on the stop ($\tilde{t}_1$) mass in natural SUSY. We first scan the
parameter space of natural SUSY in the framework of MSSM, considering the
constraints from the Higgs mass, B-physics and electroweak precision
measurements. Then in the allowed parameter space we perform a Monte Carlo
simulation for stop pair production followed by $\tilde{t}_{1} \to t
\tilde{\chi}_{1}^{0}$ or $\tilde{t}_{1} \to b \tilde{\chi}_{1}^{+}$ and sbottom
pair production followed by $\tilde{b}_{1} \to b \tilde{\chi}_{1}^{0}$ or
$\tilde{b}_{1} \to t \tilde{\chi}_{1}^{-}$. Using the combined results of ATLAS
with 20.1 fb$^{-1}$ from the search of $\ell+{\rm jets}+\slashed E_{T}$,
hadronic $t\bar{t}+\slashed E_{T}$ and $2b+\slashed E_{T}$, we find that a stop
lighter than 600 GeV can be excluded at 95% CL in this scenario.
