As the core component of wearable electronics, flexible strain sensors have played an undeniable role in production and life, receiving widespread attention. However, the challenge persists in finding a simple and environmentally friendly preparation method for high-performance flexible strain sensors. Here, we present a porous strain sensor (KCNT/PDMS-P) prepared through an emulsion method that combines modified carbon nanotubes (KCNTs), polydimethylsiloxane (PDMS), and water. The carbon nanotubes (CNTs) undergo modification using KH550 in a water/ethanol solution to enhance their interface interaction with PDMS and improve KCNT dispersion in PDMS. The improved dispersion and porous structure give the KCNT/PDMS-P strain sensor a lower percolation threshold (0.49 wt%). Additionally, the KCNT/PDMS-P with 1.5 wt% KCNTs exhibits excellent sensing performance, featuring a gauge factor (GF) of 129, a minimum strain monitoring limit of 0.1%, and the ability to monitor various strains and frequencies. In the final exploration of the sensor's practical application, we achieve effective detection of human joint motion and facial expressions.