Silk nanofibers (SNFs) from abundant sources are low-cost and environmentally friendly. Combined with other functional materials, SNFs can help create bioelectronics with excellent biocompatibility without environmental concerns. However, it is still challenging to construct an SNF-based composite with high conductivity, flexibility, and mechanical strength for all SNF-based electronics. Herein, this work reports the design and fabrication of Ti3C2Tx-silver@silk nanofibers (Ti3C2Tx-Ag@SNF) composites with multi-dimensional heterogeneous conductive networks using combined in situ growth and vacuum filtration methods. The ultrahigh electrical conductivity of Ti3C2Tx-Ag@SNF composites (142959 S m−1) provides the kirigami-patterned soft heaters with a rapid heating rate of 87 °C s−1. The multi-dimensional heterogeneous network further allows the creation of electromagnetic interference shielding devices with an exceptionally high specific shielding effectiveness of 10,088 dB cm−1. Besides working as a triboelectric layer to harvest the mechanical energy and recognize the hand gesture, the Ti3C2Tx-Ag@SNF composites can also be combined with an ionic layer to result in a capacitive pressure sensor with a high sensitivity of 410 kPa−1 in a large range due to electronic-double layer effect. The applications of the Ti3C2Tx-Ag@SNF composites in recognizing human gestures and human-machine interfaces to wirelessly control a trolley demonstrate the future development of all SNF-based electronics.