This paper investigates the penetration depth of a novel nano-modified silicate penetration crystallization material (referred to as “Nanogel”) in concrete. The research analyzed the effect of penetration time on the depth of Nanogel in concrete through chloride ion coloration assay, electron microscopy observation of penetration depth, and fine crack repair experiments in concrete. The findings indicate that the Nanogel penetrates rapidly in the early stages, with a penetration depth of 16.5 mm after 7 days. When Nanogel is applied to the surface of existing concrete, electron microscopy experiments after one month reveal a penetration depth of up to 40 mm, and after three months, the penetration reaches 60 mm. After the application of Nanogel, it reacts with the concrete to produce dendritic calcium silicate hydrate crystals, effectively filling the internal pores of the concrete, thus making the internal structure more compact. This process can automatically repair fine cracks in the concrete, thereby enhancing its durability.