Multifunctional integrated optical sensors have attracted considerable attention for their fast response and high precision. However, it remains a challenge to decouple the crosstalk on the multisensory in a single sensor to enhance reliability and practicality. Here, we present a generic strategy for introducing multiple optical parameters, a fluorescence intensity ratio, and a lifetime to monitor alterations of temperature and strain synergistically. An ultrasensitive sensing platform with suitable multiple emissions was constructed by designing luminescent metal halides to realize versatile energy transfer channels between intrinsic self-trapped excitons and dopants' emission centers. Thus, the flexible fiber was fabricated and committed to monitoring temperature and strain in real-time working conditions with precision and repeatability. Moreover, the decoupling of temperature and strain sensing can be performed by the fluorescence intensity ratio and the lifetime of the ${\mathrm{Mn}}^{2+}$ ions. This work paves the way for emerging luminescent metal halides with multiple emissions applied in advanced multifunctional optical sensors and provides the solution for decoupling the crosstalk on the multisensory to enhance its reliability and practicality.