Drought stress is a worldwide factor limiting the agricultural production. Silica nanoparticles (SiNPs) could improve plant tolerance to drought stress, but its role in ginger salt response and the behind mechanisms are still unknown. The effect of SiNP100 on drought-stressed ginger was investigated, and four treatments included CK, SiNP100, drought stress (DS), and DS+ SiNP100 were performed at 49 days after sowing. The result showed that drought stress exerts a detrimental impact on the ginger growth, photosynthetic performance, and the relative water content of plant. SiNP100 treatment significantly improved the photosynthetic (up to 72.7% increase), chlorophyll contents, and relative water content (up to 63% increase), but decreased oxidative damage, which collectively contributed to increased plant growth. Moreover, application of SiNP100 on drought stressed ginger has the potential to maintain stomatal opening and increase stomatal density through increasing leaf water potential and maintaining leaf cell integrity. The increased leaf osmotic potential (up to 35.1% increase) and leaf water potential (up to 3.6% increase) may further promote the accumulation of ABA in ginger seedlings. Furthermore, SiNP100 increased root growth and root hydraulic conductance (Lp, up to 3.6% increase), which contribute to the increased root water uptake. Further results revealed that SiNP100 can regulate water balance of ginger plants under drought conditions by up-regulating the expression of ZoAQP genes, especially in the rhizome. Under drought stress, the exogenous application of HgCl2 decreased the water loss transpiration rates of seedlings and SiNP100 alleviated this decrease. Therefore, this study can help to better understand the role of SiNP100 in alleviating drought stress and to develop further technology for plants to counteract the influence of abiotic stress.