Silicon bridge-tuned electronic structures and transport properties of polymetallocenes,[V(Cp)_{2}(SiH_{2})_{n}]_{m} (*n*=1 (**a**), *n*=2 (**b**), *n*=3 (**c**); *m*=∞; Cp=cyclopentadienyl), are studied using the densityfunctional theory (DFT) and non-equilibrium Green's function (NEGF) methods. As the silicon bridge islengthened, the V-V ferromagnetic (FM) coupling is weakened, while the antiferromagnetic (AFM) coupling isstrengthened. Polymetallocenes **a** and **b** favor the FM ground state, while **c** prefers the AFM ground state. EachV atom in the FM state of **a** and **b** has a magnetic moment of ~3.0*μ*_{B}, three times larger than that in the Vbenzeneor V-cyclopentadiene multidecker complex. The transport properties of **a**-**c** are in good agreementwith their electronic structures. Their conductivities follow the sequence **c** > **b** > **a**. For **a** and **b**, the spin-downstate has slightly higher conductivity than the spin-up state. Polymetallocenes **a** and **c** can both display evidentnegative differential resistance (NDR) behavior, while **b** cannot. This difference may originate from theorientation of the two V(Cp)_{2} units, which is V-shaped for **a** and **c** (odd number of SiH_{2} units), leading to ioniclikeinter-quantum dot coupling, and parallel for **b** (even number of SiH_{2} units), leading to covalent-like interquantumdot coupling. In addition, the conductivity of **a**-**c** is sensitive to the current direction because of theasymmetric coupling between the scattering region and two electrodes.