Electrical impedance spectroscopy (EIS) and electrolyte leakage (EL) methods were used to measure frost hardiness of stems and needles of Mongolia Scotch pine (Pinus sylvestris L. var. mongolica Litv.) saplings in different development stage. By comparing the frost hardiness results measured by the two methods, the aim of the study was to find suitable EIS parameters evaluating the frost hardiness of frost-exposed and non-frost-exposed Mongolia Scotch pine, and to optimize EIS method for studying frost hardiness on plant. Eight-year-old Mongolia Scotch pine saplings were sampled in frost hardening (October) and dehardening (March) stage for EIS and EL measurement. The results indicated that the determination coefficient of frost hardiness between EIS (re) and EL is 0.97, however, the frost hardiness results evaluated by EIS (re) was higher than those by EL. The trend of membrane time constant τm in needles and relaxation time τ1 in stems changed with the freezing temperatures showed the similar “Sigmoid function” curve as specific extracellular resistance re, and the correlation analysis showed that re (stems and needles) correlated with τ1 (stems) and τm (needles) after freezing temperature treatment (R2 =0.74～0.84). Through calculating by Logistic function, the frost hardiness of Mongolia Scotch pine measured by τ1 (stems) and τm (needles) methods had high correlations with that measured by EIS (re) and EL methods (R2 = 0.88～0.91). It suggested that τm of needles and τ1 of stems might be the parameters to calculate the frost hardiness after exposed to freezing temperatures. In addition, τm of needles and τ2 of stems in non-frost-exposed samples increased significantly with the enhanced frost hardiness in two development stages of 8-year-old Mongolia Scotch pine, indicating that τm (needles) and τ2 (stems) of non-frost-exposed saplings would be good parameters to estimate frost hardiness in Mongolia Scotch pine.