Multidimensional optical sensing is crucial in information technology and modern intelligent systems. Despite advancement in optical sensing, capturing multidimensional light field information remains challenging, typically implemented using cascaded single-dimensional sensors and discrete optoelectrical components for information decoupling. Here, we present an all-integrated multidimensional sensing chip incorporating a light field sensitizer and a photonic neural network processor. The inverse-designed sensitizer projects the multidimensional input into multiple channels; each dimension is then decoupled through the reconfigurable nonlinear neural network. We experimentally achieved 91% high accuracy for single-shot, concurrent sensing of intensity, polarization, and wavelength using a well-trained five-layer neuromorphic system. The fully on-chip system eliminates optical-electrical conversion and offline digital processing, enabling low-latency and high energy efficiency. Moreover, we achieved stabilization and recovery of high-speed signals at 100 gigabytes per second under randomly perturbed polarization and wavelengths. This work shows the potential for low-latency, energy-efficient optical sensing and complex information processing using neuromorphic integrated photonics.